<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./js/jquery.js"></script>
    <style>
        .box{
            width: 100%;
            height: 200px;
            background: skyblue;
        }
    </style>
</head>
<body>
    <button>下拉</button>
    <button>上去</button>
    <button>切换</button>
    <div class="box"></div>
    <div class="box"></div>
    <script>
        $("button").eq(0).click(function(){
            $(".box").slideDown();
        })
        $("button").eq(1).click(function(){
            $(".box").slideUp();
        })
        $("button").eq(2).click(function(){
            $(".box").slideToggle();
        })
    </script>
</body>
</html>